Australian scientists in 1961 demonstrated conclusively that wool growth could be essentially doubled when milk protein was completely protected against rumen destruction. They administered the protein postruminally by surgical methods directly into the true stomach of lambs. During the past 15 years scientists throughout the world have attempted to apply the Australian findings to feeding procedures in which surgery was not involved; and which, if successful, could be utilized in cattle or sheep feeding practices. These attempts prior to the present invention were largely unsuccessful.
Faichney et al have reported on the feeding of protected protein (viz. formaldehyde-treated peanut meal) to calves. Faichney et al, Aust. J. Agric. Res., 23, 167-175 (1972). Two protein levels were used. It was concluded that "formaldehyde treatment of peanut meal in the diet had no effect at the higher protein level and only a small, but consistent, effect at the lower protein level". Schmidt et al conducted several feeding tests in which formaldehyde-treated soybean protein was given to steers. Schmidt et al J. Anim. Sci., 37, 1233-1237 (1973); and Schmidt et al, J. Anim. Sci., 38, 645-653 (1974). The results were discouraging. In the comparative experiment reported in 1973, steers receiving untreated soybean meal supplement gained faster and tended to be more efficient than those receiving the protected soybean meal. Later tests confirmatory of these negative results were reported in the 1974 publication. No beneficial effect was found due to the treatment of the soybean protein with any of the levels of formaldehyde used.
U.S. Pat. No. 3,619,200, dated Nov. 9, 1971, describes the application to proteinaceous ruminant feed materials of a rumen resistant coating. The purpose of the coating is to protect the proteinaceous feed from microbial attack in the rumen while decomposing and permitting digestion of the feed within the abomasum and small intestine. Vegetable meals, fish meals, and a wide variety of natural proteinaceous feed materials are disclosed as useable with the rumen resistant coating. Example 2 describes the coating of fish meal and peanut meal which was mixed with equal parts of "lucerne chaff", which is understood to be an Australian term for ground alfalfa hay.